Vnx Storage Processors Test

The storage processor enables the administrator in serving the purpose of the following:

creating raid groups
binding LUNs
execute CLI commands
perform read/write operations from external server to SAN

Excessive usage of or heavy I/O load on a single storage processor can cause a marked deterioration in the overall performance of the storage sub-system, as it is indicative of severe deficiencies in the load-balancing algorithm that drives the storage processors. Using the Vnx Storage Processors test, administrators can easily monitor the current state, usage, and load on each of the storage processors on the EMC VNX storage system, quickly detect an overload condition, precisely point to the storage processor that is bearing its brunt, and promptly initiate measures to resolve the issue, so as to ensure the optimal performance of the storage system.

Target of the test : An EMC VNX Unified Storage system

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each storage processor of the EMC VNX Unified Storage system.

Configurable parameters for the test
Parameter	Description
Test Period	How often should the test be executed.
Host	The IP address of the storage device for which this test is to be configured.
Port	The port number at which the storage device listens. The default is NULL.
Controller IP	Specify the IP address of the storage controller on the block-only storage system in the Controller IP text box. By default, the IP address of the Host will be assigned in the Controller IP text box.
NaviseccliPath	The eG agent uses the command-line utility, NaviSecCli.exe, which is part of the NaviSphere Management Suite, to communicate with and monitor the storage device. To enable the eG agent to invoke the CLI, configure the full path to the CLI in the NaviseccliPath text box.
User Name and Password	Provide the credentials of a user with Administrator rights to the storage controller in the User Name and Password text boxes.
Confirm Password	Confirm the password by retyping it here.
User Scope	To use the NaviSphere CLI, the eG agent needs to be configured with a User Scope. Scope defines the access radius of the user account (User and Password) that you have configured for this test. Set User Scope to Local if the user account you have configured for this test applies to the monitored storage system only. Set User Scope to Global if the user account you have configured applies to all the storage systems within a domain.
Timeout	Indicate the duration (in seconds) for which this test should wait for a response from the storage device. By default, this is set to 120 seconds. Note that the 'Timeout' value should always be set between 3 and 600 seconds only.

Measurements made by the test

Measurement

Description

Measurement Unit

Interpretation

Busy

Indicates percent utilization of this storage processor.

Percent

A value close to 100 indicates that the storage processor is being excessively utilized. If both the processors are very busy, then it indicates that the load on the storage system is high, and that adequate resources may have to be allocated to both the processors to enable them to handle the load. If only a single processor is found to be extremely busy, it is a cause for concern, as it indicates that I/O load has not been uniformly distributed between the two processors, thus imposing additional strain on a particular processor.

Data reads

Indicates the rate at which data is read via this storage processor.

Blocks/Sec

These measures are good indicators of the I/O processing ability of the SPs. You can also compare the value of these measures across SPs to identify which SP is the slowest when handing I/O requests. By closely tracking the value of these measures for that SP over time, you can proactively detect potential processing bottlenecks and also figure out when the slowdown occurs – when reading from or writing to the storage processor?

Data writes

Indicates the rate at which data is written via this storage processor.

Blocks/Sec

Idle

Indicates the percentage of time for which this storage processor was idle.

Percent

This value varies with respect to the value of the Busy measure.

In the event of an overload/slowdown, you may want to compare the value of the Idle and Busy measures of an SP to figure out whether it has been utilized optimally or under-utilized. If the Idle measure value is greater than the value of the Busy measure, it is a clear indicator of under-utilization of a storage processor, probably caused by a poor load-balancing mechanism. You may consider fine-tuning the load balancing algorithm in such a case, to make sure that load is handled more quickly and efficiently and processing bottlenecks are cleared.

Read requests

Indicates the rate of read requests to this storage processor.

Reqs/Sec

Comparing the value of these measures across storage processors will clearly indicate which processor is overloaded - it could also shed light on irregularities in load balancing across the processors.

Write requests

Indicates the rate of write requests to this storage processor.

Reqs/Sec

Fault state

Indicates the current state of this storage processor.

A storage processor can be in the Off or in the On state. This measure can hence report one of the values – On or Off – for a storage processor.

The numeric values that correspond to the aforesaid measure values are as follows:

Measure Value	Numeric Value
Off	0
On	1

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the status of the storage processor. The graph of this measure however represents the processor status using the numeric equivalents - 0 or 1.

Total throughput

Indicates the sum of read and write request rates of this storage processor.

I/O/Sec

A consistent rise in the value of this measure is indicative of a steady increase in the I/O load of a storage processor. If this trend is observed only for one of the processors, it could hint at load-balancing irregularities. Further investigation is hence recommended.